Manufacture of modified polypropylene compositions using non-intermeshing twin screw extruder
CA 2003615 A1 · Owner: Du Pont Canada Inc. · Inventors: Kelusky, Eric C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for the grafting of alpha beta, unsaturated carboxyic acids or anhydrides onto polypropylene is disclosed. The process comprises admixing polypropylene in melt processing apparatus with 0.01 to 5% by weight of at least one of the acid and anhydride and 0.01 to 2% by weight of an organic peroxide, and extruding and recovering the grafted polypropylene. The apparatus is a twin screw extruder comprising a pair of elongated communicating barrels with parallel adjacent rotatable screws located therein, the screws having flights that are in a non-intermeshing relationship. The method results in the production of grafted polypropylene that exhibits superior adhesive properties compared, …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed November 22, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 22, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 22, 2011.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.